A heald frame has generally a square configuration formed by joining the frame staves and side stays at their respective ends. The heald frame includes also a pair of carrier rods which are vertically spaced out so that a multiplicity of healds can be secured at both ends thereto. Each of said healds accepts a warp thread passing therethrough. The heald frame is provided in a loom so as to reciprocate vertically. The heald frame is intended to travel at a higher rate of speed in a recently introduced high-speed loom and hence will bear a force of momentum in motion. Accordingly, the momentum causes deflection on each of the top and bottom frame staves which will thus be bowed inwardly and outwardly during the movements. Consequently, the deflection produces an intensive moment of bend at the joint between the frame stave and the side stay. The joint section of generally rigid construction in which the frame staves and side stays are fastened tightly can barely endure the moment of bend exerted thereon and breakage may result.
The problem of breakage is even more serious when the heald frame is provided with openings therethrough. Particularly, a heald frame of fiber reinforced plastic (RFP) reinforced with glass or carbon fibers becomes weakened when holes are provided in the frame, and this occurs because of the cutting of the fibers to provide openings in the frame. Under these circumstances, breakage is even more likely to result when the heald frame is subjected to a considerable moment of bend.